Tool lifter for machine tools



0st. 16,1945. J. DAUGHERTY 2,337,012

TOOL LIFTER FOR MACHINE TOOLS Filed April 26, 1944 2 Sheets-Sheet 1 om m N 7 mmviozz a V I Oct. .16, 1945.

. J. DAUGH ERTY.

TOOL LIFTER FOR MACHINE TOOLS 2 Sheets-Sheet 2 Filed April 26, 1944 *MJ M 3 Patented Oct. 16, 1945 t 2,387,012 TOOL LIFTER'TFOR MACHINE rooLs i Jesse Daughertyrbincinnati,0hio,;assignor to The Cincinnati Planer Company, Cincinnati, i j hio,a corporation of Ohio N I I 7 Application-April'ZG, 1944, Serial notssaao lotto- 55M I v H rstzl'aiiii This invention relates to improvements in cuttingtool lifters for machine tools; exemplifiedin a metal planer and particularly wherein "the cutting tools are of considerable size and weight; to v move the cutting tool or tools away from the contactwith the work in and for the return or re verse stroke of the work fixed upon a reciprocable work holding table or carriage to avoid injury to either the tool or work. i f

-An object ofthe invention is to provide poweroperated meansof simple construction, mounted within the tool carrying head of a planer or'other machine tool and embodying a'plunger in engage mentwith the rear side of a 'swinging'tool holder to positively actuate and maintain the holder to a position at which the cutting edge of the tool 'or'tools sustained upon the holder are out of contact or' free from the work in one stroke or direction of travel of a reciprocating work holding table or carriageand controlled by the work holding table in its'travel. Various other features and, advantages of the invention willbe more fully set forth in the following description of the'accompanying drawings forming apart of this specification, in which:

t Figure 1 is a central vertical section through a tool carrying head of a metal planer embodying the improvedtool lifter.

Figure 2 is a front elevation of the tool carrying head.

Figure 3 is an enlarged side view'of one end of the link and lever means for actuating a 'plung er abuttingly engaging the rear side of a swinging tool carrying holder. t

Figure 4 is an enlarged section Figure 2 v V Eigure 5 is an enlarged central section of' the head end of the tool carrying head corresponding toFigure 1. t'

Figure 6 is a side elevation, partly in' section of a three-way solenoid; operated valve. n Figureifisa diagrammatic view of a control circuit for the solenoid'operated valve. g In the drawingsfno discIosureismade of a complete machine .tool, as 'f orexample, a planer, to which the present improvement is particularly applicable, as it maybe of conventional structure,

of the head end on line 22,

well known inthe-art. j V

Generally in a pla'ner type of machine toolthe work is dogged or clampedupon a traversing table andmoved against a relatively fixed tool. The tablegenerally'is disposed andreciprocatesin a horizontal plane upon a bed. "The cutter usually is active one traversing stroke of the work andidle in a reverse or'return stroke of the work:

l Referring to the drawings, the

The tool is carried by a head slidable upona crossrail, which in-turn is slidable or movable upon vertical slide ways'each respectively on'a vertical housing or upright extending-upwardly above the bed of the'machine and relatively at opposite sid'thereof. -Thecross'rail thus is supported by a pair of'uprights and bridges thework, and the larger sizes of -planers'generally carry a pair of tool carrying head's.---- Itis also common practice to provide side'heads for either one or both of the housings or -uprights.-'

'As the presentimprovement is incorporated in -a tool carrying head'of a planer and as the-structure is duplicated for each head the I disclosure is confined to a single head-.- I

tool carrying head comprises a slide rest I, commonly called a harp 'and followingthe conventional practice is mounted upon a saddle, not shown; which in turn 'is mounted and translated upon the cross rail'of transmission of which gear 1, is an element in mesh withgear '5, and manually by crank handle engageable upon the'outer end of the screw.

The upper or outer end *of'the feed screw 4, traverses and is journaled in a bearing 8, extending from the rear side of a slide '9, slidably mounted upon the harp I. V

The slide 9 carries a tool block 19, pivotally mounted 'at its upper endupon' a clapper box I I, swiveledan'd clamped to the face side of the slide. The tool block lll, is pivotally mountedrin the clapper box l, toswing outwardly therefrom, thereby to elevateor move jthecutting edge of the tool I 2; away from the work. T r t The clapper bo'x' II, for the tool block,tis pivotally connected to the slide by a bushing or sleeve 13, fixed to the slide and is axially traversed by aplunger M} of the'toolj li'fti'mechanism. The outer end of the plunger 14, abuttingly engages or eon'tacts against'the'rear side ofv the swinging block of the tool-holder, and centrally thereof, adapting the plung'er when moved outwardly to correspondingly swing the tool block to lift the cutting edge of the'tool from the work. Extendaction is compounded. and is very efiective in forci;

bly moving the plunger,

The curved cam edge of the lever arin'iis generated with a relatively long radius as compared to the radius of the swing or the leven there fore is exceedingly smooth operationagaiinsit the plunger. The construction facilitates 21556111 bly, is compact, requiring buteaminimumqspaee; 7

and is quickly responsive. The cam providesflpproximately uniformly accelerated motion in'the 20 lifting movement and uniformly decelerated-motion io'f the tool block inthe return movement or drop of the toolblqck. The lever ratio of cam providesrorce where needed winch tard and cushion the movement of the piston for a determined distance toward the end of its return or retreat stroke, and thereby prevent any abrupt or sharp clap of the tool to its active or cutting position. The slow escape of the pressure medium from the cylinder checks the movement of the piston, cushioning the seating of the tool block, so as not to disturb the setting Mwthe' slide; The settinglof the s'lide must be 10 absolutely maintained, as a change as slight as I 0001" would, if repeated each cutting stroke, "cause a considerable error from machining a true .'P ar l.

' "The lifting mechanism is normalized by the pr essure of a spring 3|, housed within a guide sleeve' 3 2 engaged' and fixed within the upper end of the slide. One end of the spring 3| is pocketed a screw 33, threaded into the outer end of the sleeve 32, and its opposite end is soeketed axially within a relative end of a plun er .34, slidablerwithin thesleeve 32. The outer end of the plunger 34 bears against the outerlend of the lever M. The plunger 34 is ated inlongitudinal alignment with the cornis when unseating the tool block. The shape necting rod l1, and normalizes the lifting mechof the cam also, by slowing down the railing movement of the tool block causes the block to seat gently with a minimum effect in di turbing i er s non i e i eit The second arm of 1th lever 15, pivotallyiconnects with one endof ,a link or eonnectingrod l1, and theopposite .end of the rod l1, -pivotally connects with an arm pf a lever -l3, engaged through an aperture in the slide and'pivotally mounted upon a bracket I3,,-fixe d to the ;fa;ce sideof the slide and at the upper or outerend thereofr e v m 1/ V Theopposite arm of thelever I 3, journals a r ler eneae ev wl-i h the end of; a pistonreclfl. extend n from one side of .fl,,p iSt011.2| -IGH?IO c b e within a erticallyld p sed qyi nder-elzl. mounted up n the br cket 9, the bracketprev dinsaheadIorthecylinder-1 v 1 e A head i 3P 0VideSV31.61051 819! h i pp end of th cylinder and has a duct 24 internally thereof l ad n c ntra ly: into the ylinder a d some mummies with pressureisupplypi e: .25; em eased and threaderl'in a s de ofthe; head. The pressure supply line or pipeifi leads to and com neetswith a suitable. pressure s urce, which i cludesa valve stationed on thehead 2 and the pressure medium may comprise either air orliq uid as available. Aeportion oivthe pressure li at the end eonnectin gwithithe cylinder, ma be of. liexiblevtubing to accommodate ior the vertical travel of the crossrrail, crossieed @ithe tool carryin head and vertical. feed i. the sli .A...sleeve screw 2t is en aged centrally into the outer side :of the pistomwhich serves toiolamp the cnp -form. of-pa cking Unto the piston n as a stop for engagementwith the cvlinderhead 23, in the retreat or return stroke of the pistQn- The sleeve screwjfi isltraversed. by the,.sh nk or stem of a check valve 2 which normal y... Q 4 the-duct 24. 1. .7 a be Y v The valve extends :into a socketaxiallyeoi the pistonrod 20, and is provided with an annular flange 29; en a in anend of a s rin seated a ainst the .base of the-socketin the nistonirnd, forurging the valve against thev cylinder h ad 2. to capthe duct 24. .r Theseatingend of the valve has a :channel or groove out. across .ltsef ace. to prevent .anrabsolute closure of the duetandrrovide a ment .or escape. ofrthenpressure; med um when the pressure against the piston is out off. The tension or the spring can he res ilaitedb'y adjusting theset screw3i3.

' 'Various methods may be employed .ior controlling and timing the'operation of the lifting mechanism, relative to various lengths of traverse of the worker work carrying table. A preferred method comprises'the use or :a conventional threeway solenoid operated valve. 35, interposed. in the 5 pressure line '25 to thepismn cylinder 22. As

illustrated in Figure lithe valve is provided with a pair of .opp sitelyldisposed' spring urged valves .36, v3], operative relatively alternately thatis when one is closed thebther is open, and vice The valves a e actuated in an opening direction by a lever 38, disposed'longitndinally within a chamber 39, of the valve casing and opeiated byhsdlenoid A il mounted upon the valve casing; The lever..3,8 is'interposed between the nection therewithl a; stemslof thei'valves {IiQjL-and in contact con;-

The mannerisms; a pressure inlet port B, controlled by the valve 35 a i-second port A in pipe connection with the cylinder 22, and an exhaust'port'C, controlled by 'th'e valve 3]. When the valve .35 is open, upon energiz'ation of the solenoid. pressu e is supplied to the cylinder tor moving thefpiston to elevate the cutting tool from the work. The cutting tool is held in its elevated position until the control .of'the'valve reversed,

whereby the pressure is cut off to the cylinder, that is valve 36 is \closed and valve 37,, Qbened permitting the pressure in the cylinder to exhailstfor" a return movement of the piston co the pressure of the spring 31,

carried even arm oiaileverlfl; and through'the switc when closed; "amusement line 44; connect' .witnphe p osn lineioi a power source. *rhe'switcn tavern, is s'uitablyfnionntedjin rem tionto thatraversing morkjcarrying table 65; of

7.0 t ,planerlpr ma hmezmei amid-ifs actuated in .al-

ternate dire. us hiya pair'of dogs 45, 4B, fixed at a predetern' ined distanceia'part to "a side 'of the re. learni g table 45, The dogs are adjustably mounted upon the side of the table to a'c stroke length or travel of the table, which is variable. One of the dogs, say when the table has reached the end of a cutting stroke advancely actuates the switch lever to complete the electric circuit to energize the solenoid and effect a lifting of the cutting tool from the work, and which is held energized to hold the cutting tool from the work until the end of the return stroke of the work holding table is reached, whereupon the second dog moves the switch lever in a reverse position, to break the electric circuit to the solenoid. It is preferable to have the control setting arranged so that the tool is lifted immediately upon reaching the end of the cutting travel and in advance of the table starting on its return stroke and this follows correspondingly alternately in a forward or cutting stroke.

The electric circuit control for the solenoid operated valve is disclosed in a simplified form, may be variously modified and may be regarded as separate from the tool lifting mechanism and is merely exemplified to show a complete and concise method of operation. The valve 36, is shown as unseated when the solenoid is energized, which maybe the better practice, for the unseating force is against the pressure supply, which must be overcome. To arrange the unseating force against the pressure supply prevents the incidental application of pressure at the wrong moment, which may be due to failure of a part.

In an operation of the lifter, the dogs 46, 46 are appropriately set, gauged by the length of traverse of the work holding table, necessary for ma chining a given piece of work mounted upon the table, so that the tool lifting control is effective at an interval following the cutting tool clearing the work and before the traverse of the table is reversed. This correspondingly follows for either direction of table traverse.

Thus when a dog 46, toward the end of the table traverse trips the switch lever 43, by engagement with one of the pair of butterfly cams of the lever 43, say for lifting the tool, the switch lever is moved in a direction to close or complete an electric circuit for energizing the solenoid 40,

operating the valve 35, for supplying air pressure to the cylinder 22, thereby moving the piston 2|, forward and through the link and lever mechanism connecting with the piston lifting the tool block Ill.

The switch lever 43, is alternately brought into and out of contact at the end of each table stroke by means of the dogs 46. The switch lever 43, however, can be provided with two relatively 01iset butterfly cams, each of which is rocked by the corresponding of the relatively offset dogs 36, causing the table traverse to stop and reverse immediately upon depression of either one of the cams.

With the forward movement of the piston, the cam arm [5, moves the plunger I' l, correspondingly lifting the tool block ill. The profile of the cam arm I5, provides approximately uniformly accelerated motion in the lifting movement and corresponding uniformly decelerated movement of the tool block in its drop. The cam arm l5, at the end of a tool lifting swing has its tip end in engagement with the plunger l4, thereby is self-locking, so as to prevent damage through failure of operation of any part of the lifting mechanism. The shape of the cam of the arm 15, and the checking of the movement of the piston by the check valve 28, in its control of the exhaust from the cylinder, combine to prevent any abrupt seating of the tool block.

As theltension of the spring 3|, is Iregulatable by the screw 33, the normalizing pressure upon the/lifting mechanism may be varied to compensate for variation in manufacture and the weight of difierent sizes of tools as a further accommodation for a smooth and efficient operation of the mechanism.

The power cylinder is preferably mounted'upon the front and top end of the slide as a convenient location for ready accessibility for making repairs as in replacement of the packing andspring for the check valve.

Having described my invention, I claim:

1. A tool lifter for a tool sustaining head of a machine tool embodying a slide, a tool holder hingedly mounted upon the slide, a plunger carried by the slide having an end engaging the tool holder to swing the same to clear its cutting tool from the work mounted upon a traversing support, a lever mounted within the slide having a crank arm provided with a curved edge for sliding engagement with the inner end of said plunger, a link longitudinally of the slide having one end connecting with said lever, a second lever on said slideconnecting with the opposite end of said link and pressure operated means operatively connecting with said second lever.

2. A tool lifter for a tool sustaining head of a machine tool embodying a slide, a tool holder hingedly mounted upon the slide, a plunger carried by the slide having an end engaging the tool holder to swing the same to clear its cutting tool from the work mounted upon a traversing support, a lever mounted within the slide having a crank arm provided with a curved edge for sliding engagement with the inner end of said plunger, the curved edge of said crank arm generated with a relative long radius as compared to the radius of swing of the lever, a link longitudinally of the slide having one end connecting with said lever, a second lever on said slide connecting with the opposite end of said link and pressure operated means operatively connecting with said second lever. v

3. A tool lifter for a tool sustaining head of a machine tool embodying a slide, a tool holder hingedly mounted upon the slide, a plunger carried by the slide having an end engaging the tool holder to swing the same to clear its cutting tool from the work mounted upon a traversing support, a lever mounted within the slide having a crank arm provided with a curved edge for sliding engagement with the inner end of said plunger, the curved edge of said crank arm generated with a relative long radius as compared to radius of swing of the lever, a link longitudinally of the slide having one end connecting with said lever, a second lever on said slide connecting with the opposite end of said link, pressure operated means operatively connecting with said second lever and tension means within the slide for normalizing said movable parts upon release of the pressure to said pressure operated means.

4. A tool lifter for a tool sustaining head of a machine tool embodying a slide, a tool holder hingedly mounted upon a slide, a plunger carried by the slide having an end engaging the tool holder to swing the same to clear its cutting tool from the work mounted upon a traversing support, a lever mounted within the slide having a crank arm provided with a curved edge for sliding engagement with the inner end of said plunger,- the curved edge of said crank arm generated with a relative long radius as compared 4 nesweorz so she radius of swing. 101 she lever, .arlink'. longi- "bualinal'ly of the slide having zone end "connecting said lever, :a second lever on said slide eonneeuing with the nppesite end or said iimgipressure :eper-ated lmeansreperatively connectingiwiuh .seid' sentinel lever, and sa. spring urged plunger within said slide coaxially with said'limk'aml engagement with one :end thereof for normalizin said movable :parts upon release of the pressure ho-said pressurenctuated means. i i

V :5; Ato'ol llai ftel' fm. a soul sustaining head of :a machine tool embodying a slide, a tool helrler mounted lon said'slide and hingiecll-y movable to swing the same to clean its emitting :tonl from the wan-kmounted upon :a traversing s-supgoort, link and lever means mmunised :on said slide :forswinging said tool holder, 3, cylinder mounted on said --s'1ide having a, :piston reciprocable wherein, providing a :pressureeperafued means for actuating said linkand lever means to iift' the l1CI1d9I ,'if,

spring urged means ror normalizing said piston and :andilever means upon release :of the pressure to said cylinder and a spring urged check-valve:carried by the piston for :oontrolling the pressure exhaust-from the cylinder toward ,25

the end 11f the return stroke :of. the piston :to retard the normalizing movement. .i V

6. 5A tonl .lif ter zfior :a 1:001 sustaining rhea-dim a machine tooiembodyingaslide, a tool holder hinged'ly mounted on said slide a .plunger car- .riefi flayxthe slide having an enclmh-ereof in abu'izting engagement wiiih the tool holder to :swing the same, to .clear its suiting 1:001 irom the work, and lever means mounted on said slide for actuating said plunger, the lever having aJcra/nk JESSE DAUGHERFTY. I f 

